Magnetic circuit

About: Magnetic circuit is a research topic. Over the lifetime, 15707 publications have been published within this topic receiving 118099 citations.

Magnetic equivalent circuits

Abstract: The possibilities of using magnetic, instead of electric, equivalent circuits for eddy-current devices, which have recently been pointed out by Laithwaite, are here explored further. Couplings between distributed flux paths and windings can be expressed in terms of a generalised linkage parameter N, which is associated with flux linkage in electric circuits, and with an analogous current linkage in the magnetic equivalent. The magnetic-circuit treatment extends to rotating, as well as to static, devices, and leads to a view of induction machines as nonpassive magnetic elements. The relationships between the energy flow through the terminals, the mechanical forces and the magnetic terminal parameters are examined, and an alternative equivalent circuit, in which the analogue of current is not the flux but its rate of change, is shown to be in many respects a more useful one. The force equations are applicable, in particular, to devices in which induced currents are important.

Harmonic field calculation by the combination of finite element analysis and harmonic balance method

Abstract: A finite-element-method (FEM) time-periodic magnetic-field calculation is described. An AC calculation involving saturation characteristics requires many iterations and much storage space. The combination of FEM and the harmonic balance method enables the harmonic magnetic flux distribution under AC magnetization to be calculated economically. The method is applied to the magnetic-field analysis of a reactor and an electromagnet. >

Multipole electrical circuit breaker with improved interchangeable trip units

Abstract: A molded case multi-pole circuit breaker comprises an interchangeable trip unit having a magnetic circuit surrounding a main stationary conductor and provided with a U-shaped core secured to circuit-breaker assembly and a magnetic rod fastener to the trip unit. The rod is inserted between the legs of the core, and a single turn secondary winding surrounds the rod. A bimetal is attached to the winding, and the thermal tripping characteristics are independent of the relative position of the magnetic core and rod.

Normal conducting bending electromagnet

Abstract: A normal conducting bending electromagnet having: a pair of pole pieces having respective pole piece faces, said pole pieces being; disposed with the pole piece faces thereof facing each other with a substantially constant gap therebetween; a magnetic field for forming a charged particle beam arc orbit, being generated in the gap between the pole pieces. A yoke coupled to the pole pieces for forming a closed magnetic circuit with the gap, and a pair of coils is provided for generating a magnetomotive force and generating magnetic fluxes in the magnetic circuit. At least one side wall of each of the pole pieces is slanted or stepped along a virtual slanted plane; along the magnetic path of the pole piece so as to gradually broaden the cross sectional area of the pole piece at the plane perpendicular to the magnetic path from the gap toward the yoke, the slanted side wall or the virtual slanted plane; having a slant angle in the range from 30° or smaller relative to the pole piece faces, the width of the pole piece face being in the range from 4 cm or wider to 20 cm and the height of the gap along the magnetic path being in the range from 1 cm or higher to 6 cm. The normal conducting bending electromagnet can generate a strong magnetic field and reduce the orbit radius of an electron storage ring.

A novel approach to detect short circuits in low voltage induction motor by stray flux measurement

Abstract: This paper, after a detailed literature analysis, presents new results which show the actual possibility to detect inter-turn short-circuits in low voltage induction motors by means of measurements of the stray flux around the motor. With respect to the literature, some novelties are introduced: the use of different flux probes in different positions around the machine and the statistical evaluation of the experimental results. The effectiveness of the flux as diagnostic indicator has been compared to the motor current signal analysis (MCSA).